Apparatus for ore concentration



s. MALKE 2,057,338

APPARATUS FOR ORE CONCENTRATION Filed March 29, 1935 INVENTOR. Sven Malkle XZW ATTORNEY.

Patented Oct. 13, 1936 UNITED [STATES APPARATUS FOR ORE CONCENTRATION Sven Malke, Milwaukee, Wis.,, assignor to A. 0.

Smith Corporation, Milwaukee, Wis., a corporation of New York Application March 29, 1935, Serial No. 13,613

4 Claims. (Cl. 209452) This invention relates to apparatus for concentration of ores. An object of the invention is to provide improved apparatus of this kind suitable for use in the concentration of ores and the separation of the valuable constituents in ores from the other materials with which they may be mixed. Other objectsof the invention will be clear from the accompanying detailed description and the drawing in which:

Figure 1 is a longitudinal section through an embodiment of my invention;

Fig. 2 is an elevation of the right-hand end of the apparatus shown in Figure 1; and

Fig. 3 is a section through the concentrate discharge end taken on line 3-3 of Figure 1.

The ore concentrator of this invention comprises an outer drum I which may have the form of two frustums of cones joined together, as indicated in the drawing, or which may be of cylindrical, ,or other form, arranged to rotate about a horizontal axis or about an axis inclined to the horizontal. The inside surface of the outer drum is provided with a helix 2. The helix may 2 be of uniform pitch, or of a-variable pitch with the pitch decreasing toward the smaller end of the drum, as illustrated in the drawing. In

some cases, the decreasing pitch toward the" small end of the drum is of advantage; in others, a uniform pitch is more suitable. In any event, it is desirable that the rib which forms the helix should decrease in height as it approaches the small end of the drum.

An inner drum .3 is mounted rigidly within the outer drum and concentric with it. The inner drum has a.helix 4 on its inner surface. Either one or both of the helixes may be formed from a single rib or from several ribs. In the embodiment of my invention shown in the drawing both helixes are formed from a single rib, and the helix on the inner drum is so arranged as to feed in the same direction as the helix on the inner surface of the outer drum. The rib which forms the helix 4 may desirably decrease 45 in height as the outer end of the drum is approached. The rigid connection between the inner and outer drums is provided by the helix 55 or the helix which are secured to both the inner and outer drums, all the material which is fed into the large end of the outer drum is forced into the middle section of this drum. From here it can be discharged only through the inner drum or through the small end of the outer drum. No water or other material can run back over the top of the rib in the outer drum and escape at the opening left for the entrance of the feed pipe. A water level, such as is indicated in Fig. 1, will be maintained, even though the 10 drum is not in rotation, because of the inability of the water to pass from one convolution to the next one except by flowing over the top of the rib which separates them.

A cover It is securely fastened to the small, or 15 left-hand, end of the drum I. "The cover 'I is provided 'with a spout 8, as indicated in Fig. 3

which is a section through' the cover on line 3-3 of Fig. 1. As the drum rotates, the spout 8 discharges concentrates into the trough 9 which 20 serves to convey them to any desired place for further treatment.

A shaft I0 is securely fastened to the cover I and rotates. in bearing II carried by the'support I2. A pulley I3 serves for driving the drum, but other means for I rotating the drum may be used.

The other end of the drum may be supported by an open spider It which is rigidly secured to the inner drum 3 and the shaft l5. The shaft I5 rotates in a bearing I B carried by asupport II. The shaft I5 is desirably made hollow so as to provide for the introduction of a spray pipe I8 for spraying water upon the material being treated. A trough I9 is provided for carrying away tailings discharged from the open end of the inner drum 3.

In the operation of this machine, the drums are set in rotation. The direction of rotation is such that the tendency of the helixes 2 and 4 40 is to drive any material which they contain from right to left, or from the large end of the outer drum to the small end. The drum may be rotated continuously in one direction, either at a constant or a varying speed, or it may be given 5 an oscillatory rotation with a preponderance of movement in one direction. A pulp of ground ore and water is fed into the outer drumthrough the feed pipe 6.

Both the valuable constituent of the ore, such as gold, and the valueless sand, or other 'gangue with which it may be mixed, move initially in the same direction, that is, from the large end of, the outer drum toward the small end, or from thefeed end toward the concentrate discharge end. During this initial motion, the heavy particles of gold, or other valuable material, sink through the pulp and tend to collect near the bottom. The pulp which is thus stratified then passes beyond the end of the inner drum 3 and is exposed to the action of jets of water issuing from holes 20 in the spray pipe Ill. The jets are preferably so directed as to cause the water spray to impinge upon the inner wall of the drum at the place where the rising side of the rotating drum leaves the pulp. The jets of water wash off impurities from the heavy particles of gold, or other valuable mineral being separated. Thetailings of the lighter and less valuable material are washed backward by the water and are ultimately discharged through the open end of the inner drum into a trough H which carries them away for disposal.

The heavy constituents 'seek the lowest level in the apparatus. They lodge at the bottom of the helix and are thus kept from being swept away with the tailings. The continued rotation of the drum drives the valuable constituents forward untilthey are ultimately discharged through the nozzle 8 into a trough 9 provided for their reception. As the ribs of the helix 2 are made to de crease in height as the concentrate discharge end is approached, more and more of the lighter valueless material is forced above the convolutions of the helix and is swept away to the tailings discharge. Consequently, a cleanengr higher grade concentrate is produced than if the helix were maintained of uniform height throughout its entire course.

While the jets of water from the spray pipe are of considerable assistance to the production of an effective separation, they are not indispensable to the successful operation of the machine since,

even in their absence, the continued rotation of the drum will result in forcing concentrates out of one end, and tailings out of the other.

Before the tailings are discharged from the machine they must pass through the inner drum 3, which is provided with the helix 4 having a pitch in the same direction as the pitch of helix 2. This helix therefore propels heavy materials which lodge in it in a forward direction. Any gold particles which may have been carried with the tailings into the inner drum are caught in this drum and returned to the outer drum to be discharged at the concentrate end. The inner drum thus makes for tailings which contain little or no values, that is, fora high degree of. recovery of the valuable material in the ore being treated.

The inner drum may have the shape of a frustum' of a cone, as shown in the drawing, and may be provided with'a helix which decreases in height toward the tailings discharge end'.--'but"the"s'e' features, while desirable, are not essential for the performance of the important function of the inner drum of thoroughly cleaning the tailings and guarding against the loss of values.

It is to be noticed that with this apparatus for concentrating ores, the valuable material and the gangue are initially moved in the same direction to produce an initial stratification of the pulp, and that the pulp is then subjected to the action of forces which produce a separation of the valuable and valueless materials by movingv one. material tailings will be discharged at whathas been termed the concentrate discharge end of the machine, while the concentrate of the lighter material will come out of the open end of the inner drum.

I claim:

1. An oreconcentrator which comprises a drum of circular cross section having the form of two frustums of cones joined together at their meeting line, thetwo frustums being from cones of different apex angles and so arranged that in both the apex falls to the same side of the frustum;

a helix coiled on the inner surface of the drum with=convolutions decreasing in depth as the helix approaches the smaller end of the drum; a second drum mounted rigidly within and concentric with the outer drum, said inner drum extending longitudinally beyond the larger end of the outer drum and longitudinally within the outer drum for only a portion of the distance from its larger to its smaller end; a helix arranged 'on the inner surface of the inner drum with a pitch in the same sense as'thepitch of the helixon the outer drum; means for rotating said drums about'their common axis; and means for feeding ore to the large end of the outer drum.

2. In an ore concentrator, the combination of a rotatable drum; a second drum mounted within the first drum; a helix on the inner surface of the outer drum; and a helix on the inner surface of the inner drum, the pitch of both helixes having the same sense, and not less than aboutone complete convolution of the rib which forms the helix on the inner surface of the outer drum being sealed to both the inner surface of the outer drum and the outer surface of the inner drum.

4 3. In an ore concentrator the combination of a rotatable drum, a helix on the inner surface of the drum, and a second drum arranged within said helix, not less than about one complete convolution of the helix being sealed to both the inner surface of the outer drum and the outer surface of the inner drum.

4. In an ore separator, the combination which comprises a rotatable drum provided with a helix on its inner surface, means for feeding a pulp of ore and water to one end of said drum, means for discharging concentrate from the opposite end of said drum, and a second drum for discharging tailings, said second drum being mounted interiorlyof the first drum and extending from beyond the feed end of the first drum to apositlon intermediate its ends, and being sealed rmediate the ends of the first drum to not less than about one complete convolution of the helix on the, inner surface of the first drum. 

